<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/pwm, branch linux-6.11.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>pwm: Assume a disabled PWM to emit a constant inactive output</title>
<updated>2024-12-05T12:53:05+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@baylibre.com</email>
</author>
<published>2024-11-05T15:35:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6e2cb93e54fafd45a631d78a5bc6a71e752359de'/>
<id>6e2cb93e54fafd45a631d78a5bc6a71e752359de</id>
<content type='text'>
[ Upstream commit b2eaa1170e45dc18eb09dcc9abafbe9a7502e960 ]

Some PWM hardwares (e.g. MC33XS2410) cannot implement a zero duty cycle
but can instead disable the hardware which also results in a constant
inactive output.

There are some checks (enabled with CONFIG_PWM_DEBUG) to help
implementing a driver without violating the normal rounding rules. Make
them less strict to let above described hardware pass without warning.

Reported-by: Dimitri Fedrau &lt;dima.fedrau@gmail.com&gt;
Link: https://lore.kernel.org/r/20241103205215.GA509903@debian
Fixes: 3ad1f3a33286 ("pwm: Implement some checks for lowlevel drivers")
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Reviewed-by: Dimitri Fedrau &lt;dima.fedrau@gmail.com&gt;
Tested-by: Dimitri Fedrau &lt;dima.fedrau@gmail.com&gt;
Link: https://lore.kernel.org/r/20241105153521.1001864-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b2eaa1170e45dc18eb09dcc9abafbe9a7502e960 ]

Some PWM hardwares (e.g. MC33XS2410) cannot implement a zero duty cycle
but can instead disable the hardware which also results in a constant
inactive output.

There are some checks (enabled with CONFIG_PWM_DEBUG) to help
implementing a driver without violating the normal rounding rules. Make
them less strict to let above described hardware pass without warning.

Reported-by: Dimitri Fedrau &lt;dima.fedrau@gmail.com&gt;
Link: https://lore.kernel.org/r/20241103205215.GA509903@debian
Fixes: 3ad1f3a33286 ("pwm: Implement some checks for lowlevel drivers")
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Reviewed-by: Dimitri Fedrau &lt;dima.fedrau@gmail.com&gt;
Tested-by: Dimitri Fedrau &lt;dima.fedrau@gmail.com&gt;
Link: https://lore.kernel.org/r/20241105153521.1001864-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: imx27: Workaround of the pwm output bug when decrease the duty cycle</title>
<updated>2024-12-05T12:53:01+00:00</updated>
<author>
<name>Clark Wang</name>
<email>xiaoning.wang@nxp.com</email>
</author>
<published>2024-10-08T19:41:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e6d94a5777b4db1067a09c0b9d325be2bbabd52d'/>
<id>e6d94a5777b4db1067a09c0b9d325be2bbabd52d</id>
<content type='text'>
[ Upstream commit a25351e4c7740eb22561a3ee4ef17611c6f410b0 ]

Implement workaround for ERR051198
(https://www.nxp.com/docs/en/errata/IMX8MN_0N14Y.pdf)

PWM output may not function correctly if the FIFO is empty when a new SAR
value is programmed.

Description:
  When the PWM FIFO is empty, a new value programmed to the PWM Sample
  register (PWM_PWMSAR) will be directly applied even if the current timer
  period has not expired. If the new SAMPLE value programmed in the
  PWM_PWMSAR register is less than the previous value, and the PWM counter
  register (PWM_PWMCNR) that contains the current COUNT value is greater
  than the new programmed SAMPLE value, the current period will not flip
  the level. This may result in an output pulse with a duty cycle of 100%.

Workaround:
  Program the current SAMPLE value in the PWM_PWMSAR register before
  updating the new duty cycle to the SAMPLE value in the PWM_PWMSAR
  register. This will ensure that the new SAMPLE value is modified during
  a non-empty FIFO, and can be successfully updated after the period
  expires.

Write the old SAR value before updating the new duty cycle to SAR. This
avoids writing the new value into an empty FIFO.

This only resolves the issue when the PWM period is longer than 2us
(or &lt;500kHz) because write register is not quick enough when PWM period is
very short.

Reproduce steps:
  cd /sys/class/pwm/pwmchip1/pwm0
  echo 2000000000 &gt; period     # It is easy to observe by using long period
  echo 1000000000 &gt; duty_cycle
  echo 1 &gt; enable
  echo       8000 &gt; duty_cycle # One full high pulse will be seen by scope

Fixes: 166091b1894d ("[ARM] MXC: add pwm driver for i.MX SoCs")
Reviewed-by: Jun Li &lt;jun.li@nxp.com&gt;
Signed-off-by: Clark Wang &lt;xiaoning.wang@nxp.com&gt;
Signed-off-by: Frank Li &lt;Frank.Li@nxp.com&gt;
Link: https://lore.kernel.org/r/20241008194123.1943141-1-Frank.Li@nxp.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a25351e4c7740eb22561a3ee4ef17611c6f410b0 ]

Implement workaround for ERR051198
(https://www.nxp.com/docs/en/errata/IMX8MN_0N14Y.pdf)

PWM output may not function correctly if the FIFO is empty when a new SAR
value is programmed.

Description:
  When the PWM FIFO is empty, a new value programmed to the PWM Sample
  register (PWM_PWMSAR) will be directly applied even if the current timer
  period has not expired. If the new SAMPLE value programmed in the
  PWM_PWMSAR register is less than the previous value, and the PWM counter
  register (PWM_PWMCNR) that contains the current COUNT value is greater
  than the new programmed SAMPLE value, the current period will not flip
  the level. This may result in an output pulse with a duty cycle of 100%.

Workaround:
  Program the current SAMPLE value in the PWM_PWMSAR register before
  updating the new duty cycle to the SAMPLE value in the PWM_PWMSAR
  register. This will ensure that the new SAMPLE value is modified during
  a non-empty FIFO, and can be successfully updated after the period
  expires.

Write the old SAR value before updating the new duty cycle to SAR. This
avoids writing the new value into an empty FIFO.

This only resolves the issue when the PWM period is longer than 2us
(or &lt;500kHz) because write register is not quick enough when PWM period is
very short.

Reproduce steps:
  cd /sys/class/pwm/pwmchip1/pwm0
  echo 2000000000 &gt; period     # It is easy to observe by using long period
  echo 1000000000 &gt; duty_cycle
  echo 1 &gt; enable
  echo       8000 &gt; duty_cycle # One full high pulse will be seen by scope

Fixes: 166091b1894d ("[ARM] MXC: add pwm driver for i.MX SoCs")
Reviewed-by: Jun Li &lt;jun.li@nxp.com&gt;
Signed-off-by: Clark Wang &lt;xiaoning.wang@nxp.com&gt;
Signed-off-by: Frank Li &lt;Frank.Li@nxp.com&gt;
Link: https://lore.kernel.org/r/20241008194123.1943141-1-Frank.Li@nxp.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: imx-tpm: Use correct MODULO value for EPWM mode</title>
<updated>2024-11-14T12:21:05+00:00</updated>
<author>
<name>Erik Schumacher</name>
<email>erik.schumacher@iris-sensing.com</email>
</author>
<published>2024-10-25T08:37:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b2c625a19bcf86b377f5fbad90118101746da975'/>
<id>b2c625a19bcf86b377f5fbad90118101746da975</id>
<content type='text'>
commit cc6a931d1f3b412263d515fd93b21fc0ca5147fe upstream.

The modulo register defines the period of the edge-aligned PWM mode
(which is the only mode implemented). The reference manual states:
"The EPWM period is determined by (MOD + 0001h) ..." So the value that
is written to the MOD register must therefore be one less than the
calculated period length. Return -EINVAL if the calculated length is
already zero.
A correct MODULO value is particularly relevant if the PWM has to output
a high frequency due to a low period value.

Fixes: 738a1cfec2ed ("pwm: Add i.MX TPM PWM driver support")
Cc: stable@vger.kernel.org
Signed-off-by: Erik Schumacher &lt;erik.schumacher@iris-sensing.com&gt;
Link: https://lore.kernel.org/r/1a3890966d68b9f800d457cbf095746627495e18.camel@iris-sensing.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cc6a931d1f3b412263d515fd93b21fc0ca5147fe upstream.

The modulo register defines the period of the edge-aligned PWM mode
(which is the only mode implemented). The reference manual states:
"The EPWM period is determined by (MOD + 0001h) ..." So the value that
is written to the MOD register must therefore be one less than the
calculated period length. Return -EINVAL if the calculated length is
already zero.
A correct MODULO value is particularly relevant if the PWM has to output
a high frequency due to a low period value.

Fixes: 738a1cfec2ed ("pwm: Add i.MX TPM PWM driver support")
Cc: stable@vger.kernel.org
Signed-off-by: Erik Schumacher &lt;erik.schumacher@iris-sensing.com&gt;
Link: https://lore.kernel.org/r/1a3890966d68b9f800d457cbf095746627495e18.camel@iris-sensing.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: stm32: Use the right CCxNP bit in stm32_pwm_enable()</title>
<updated>2024-09-05T09:12:01+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@baylibre.com</email>
</author>
<published>2024-09-05T09:06:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=10c48e9a8fd5e524d37559cf4a06039b4c25db48'/>
<id>10c48e9a8fd5e524d37559cf4a06039b4c25db48</id>
<content type='text'>
The pwm devices for a pwm_chip are numbered starting at 0, the first hw
channel however has the number 1. While introducing a parametrised macro
to simplify register bit usage and making that offset explicit, one of
the usages was converted wrongly. This is fixed here.

Fixes: 7cea05ae1d4e ("pwm-stm32: Make use of parametrised register definitions")
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Link: https://lore.kernel.org/r/20240905090627.197536-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The pwm devices for a pwm_chip are numbered starting at 0, the first hw
channel however has the number 1. While introducing a parametrised macro
to simplify register bit usage and making that offset explicit, one of
the usages was converted wrongly. This is fixed here.

Fixes: 7cea05ae1d4e ("pwm-stm32: Make use of parametrised register definitions")
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Link: https://lore.kernel.org/r/20240905090627.197536-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>of: remove internal arguments from of_property_for_each_u32()</title>
<updated>2024-07-25T11:53:47+00:00</updated>
<author>
<name>Luca Ceresoli</name>
<email>luca.ceresoli@bootlin.com</email>
</author>
<published>2024-07-24T16:33:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9722c3b66e21ff08aec570d02a97d331087fd70f'/>
<id>9722c3b66e21ff08aec570d02a97d331087fd70f</id>
<content type='text'>
The of_property_for_each_u32() macro needs five parameters, two of which
are primarily meant as internal variables for the macro itself (in the
for() clause). Yet these two parameters are used by a few drivers, and this
can be considered misuse or at least bad practice.

Now that the kernel uses C11 to build, these two parameters can be avoided
by declaring them internally, thus changing this pattern:

  struct property *prop;
  const __be32 *p;
  u32 val;

  of_property_for_each_u32(np, "xyz", prop, p, val) { ... }

to this:

  u32 val;

  of_property_for_each_u32(np, "xyz", val) { ... }

However two variables cannot be declared in the for clause even with C11,
so declare one struct that contain the two variables we actually need. As
the variables inside this struct are not meant to be used by users of this
macro, give the struct instance the noticeable name "_it" so it is visible
during code reviews, helping to avoid new code to use it directly.

Most usages are trivially converted as they do not use those two
parameters, as expected. The non-trivial cases are:

 - drivers/clk/clk.c, of_clk_get_parent_name(): easily doable anyway
 - drivers/clk/clk-si5351.c, si5351_dt_parse(): this is more complex as the
   checks had to be replicated in a different way, making code more verbose
   and somewhat uglier, but I refrained from a full rework to keep as much
   of the original code untouched having no hardware to test my changes

All the changes have been build tested. The few for which I have the
hardware have been runtime-tested too.

Reviewed-by: Andre Przywara &lt;andre.przywara@arm.com&gt; # drivers/clk/sunxi/clk-simple-gates.c, drivers/clk/sunxi/clk-sun8i-bus-gates.c
Acked-by: Bartosz Golaszewski &lt;bartosz.golaszewski@linaro.org&gt; # drivers/gpio/gpio-brcmstb.c
Acked-by: Nicolas Ferre &lt;nicolas.ferre@microchip.com&gt; # drivers/irqchip/irq-atmel-aic-common.c
Acked-by: Jonathan Cameron &lt;Jonathan.Cameron@huawei.com&gt; # drivers/iio/adc/ti_am335x_adc.c
Acked-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt; # drivers/pwm/pwm-samsung.c
Acked-by: Richard Leitner &lt;richard.leitner@linux.dev&gt; # drivers/usb/misc/usb251xb.c
Acked-by: Mark Brown &lt;broonie@kernel.org&gt; # sound/soc/codecs/arizona.c
Reviewed-by: Richard Fitzgerald &lt;rf@opensource.cirrus.com&gt; # sound/soc/codecs/arizona.c
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt; # arch/powerpc/sysdev/xive/spapr.c
Acked-by: Stephen Boyd &lt;sboyd@kernel.org&gt; # clk
Signed-off-by: Luca Ceresoli &lt;luca.ceresoli@bootlin.com&gt;
Acked-by: Lee Jones &lt;lee@kernel.org&gt;
Link: https://lore.kernel.org/r/20240724-of_property_for_each_u32-v3-1-bea82ce429e2@bootlin.com
Signed-off-by: Rob Herring (Arm) &lt;robh@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The of_property_for_each_u32() macro needs five parameters, two of which
are primarily meant as internal variables for the macro itself (in the
for() clause). Yet these two parameters are used by a few drivers, and this
can be considered misuse or at least bad practice.

Now that the kernel uses C11 to build, these two parameters can be avoided
by declaring them internally, thus changing this pattern:

  struct property *prop;
  const __be32 *p;
  u32 val;

  of_property_for_each_u32(np, "xyz", prop, p, val) { ... }

to this:

  u32 val;

  of_property_for_each_u32(np, "xyz", val) { ... }

However two variables cannot be declared in the for clause even with C11,
so declare one struct that contain the two variables we actually need. As
the variables inside this struct are not meant to be used by users of this
macro, give the struct instance the noticeable name "_it" so it is visible
during code reviews, helping to avoid new code to use it directly.

Most usages are trivially converted as they do not use those two
parameters, as expected. The non-trivial cases are:

 - drivers/clk/clk.c, of_clk_get_parent_name(): easily doable anyway
 - drivers/clk/clk-si5351.c, si5351_dt_parse(): this is more complex as the
   checks had to be replicated in a different way, making code more verbose
   and somewhat uglier, but I refrained from a full rework to keep as much
   of the original code untouched having no hardware to test my changes

All the changes have been build tested. The few for which I have the
hardware have been runtime-tested too.

Reviewed-by: Andre Przywara &lt;andre.przywara@arm.com&gt; # drivers/clk/sunxi/clk-simple-gates.c, drivers/clk/sunxi/clk-sun8i-bus-gates.c
Acked-by: Bartosz Golaszewski &lt;bartosz.golaszewski@linaro.org&gt; # drivers/gpio/gpio-brcmstb.c
Acked-by: Nicolas Ferre &lt;nicolas.ferre@microchip.com&gt; # drivers/irqchip/irq-atmel-aic-common.c
Acked-by: Jonathan Cameron &lt;Jonathan.Cameron@huawei.com&gt; # drivers/iio/adc/ti_am335x_adc.c
Acked-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt; # drivers/pwm/pwm-samsung.c
Acked-by: Richard Leitner &lt;richard.leitner@linux.dev&gt; # drivers/usb/misc/usb251xb.c
Acked-by: Mark Brown &lt;broonie@kernel.org&gt; # sound/soc/codecs/arizona.c
Reviewed-by: Richard Fitzgerald &lt;rf@opensource.cirrus.com&gt; # sound/soc/codecs/arizona.c
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt; # arch/powerpc/sysdev/xive/spapr.c
Acked-by: Stephen Boyd &lt;sboyd@kernel.org&gt; # clk
Signed-off-by: Luca Ceresoli &lt;luca.ceresoli@bootlin.com&gt;
Acked-by: Lee Jones &lt;lee@kernel.org&gt;
Link: https://lore.kernel.org/r/20240724-of_property_for_each_u32-v3-1-bea82ce429e2@bootlin.com
Signed-off-by: Rob Herring (Arm) &lt;robh@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: axi-pwmgen: add .max_register to regmap</title>
<updated>2024-07-11T13:44:40+00:00</updated>
<author>
<name>Trevor Gamblin</name>
<email>tgamblin@baylibre.com</email>
</author>
<published>2024-07-11T12:57:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=240b129d597cb8a8880eb3a381ff10eb98ca0c07'/>
<id>240b129d597cb8a8880eb3a381ff10eb98ca0c07</id>
<content type='text'>
This was missed in the basic driver and is useful for debug, so add it.

Example regmap output before the patch:

|root@zed-tg:~# cat /sys/kernel/debug/regmap/44a60000.pwm/registers
|0: 00020100

And with it:

|root@zed-tg:~# cat /sys/kernel/debug/regmap/44a60000.pwm/registers
|00: 00020100
|04: 00000000
|08: 00000000
|0c: 601a3471
|10: 00000000
|14: 00000002
|18: 00000001
|1c: 00000000
|...

Signed-off-by: Trevor Gamblin &lt;tgamblin@baylibre.com&gt;
Link: https://lore.kernel.org/r/20240711125743.3956935-1-tgamblin@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This was missed in the basic driver and is useful for debug, so add it.

Example regmap output before the patch:

|root@zed-tg:~# cat /sys/kernel/debug/regmap/44a60000.pwm/registers
|0: 00020100

And with it:

|root@zed-tg:~# cat /sys/kernel/debug/regmap/44a60000.pwm/registers
|00: 00020100
|04: 00000000
|08: 00000000
|0c: 601a3471
|10: 00000000
|14: 00000002
|18: 00000001
|1c: 00000000
|...

Signed-off-by: Trevor Gamblin &lt;tgamblin@baylibre.com&gt;
Link: https://lore.kernel.org/r/20240711125743.3956935-1-tgamblin@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: atmel-tcb: Make private data variable naming consistent</title>
<updated>2024-07-10T15:55:38+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@baylibre.com</email>
</author>
<published>2024-07-09T09:22:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c9a787b9456066d4bd34522f880bd16208d775dd'/>
<id>c9a787b9456066d4bd34522f880bd16208d775dd</id>
<content type='text'>
Currently the variables of type struct atmel_tcb_pwm_device
are named "tcbpwm", and variables of type atmel_tcb_pwm_chip are either
named "tcbpwm" (too!) or "tcbpwmc". Rename the chips with device name to
"tcbpwmc" to get a consistent naming.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Acked-by: Nicolas Ferre &lt;nicolas.ferre@microchip.com&gt;
Link: https://lore.kernel.org/r/20240709092221.47025-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently the variables of type struct atmel_tcb_pwm_device
are named "tcbpwm", and variables of type atmel_tcb_pwm_chip are either
named "tcbpwm" (too!) or "tcbpwmc". Rename the chips with device name to
"tcbpwmc" to get a consistent naming.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Acked-by: Nicolas Ferre &lt;nicolas.ferre@microchip.com&gt;
Link: https://lore.kernel.org/r/20240709092221.47025-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: atmel-tcb: Simplify checking the companion output</title>
<updated>2024-07-10T15:55:12+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@baylibre.com</email>
</author>
<published>2024-07-09T10:18:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c1330cb9a56d42632b1af54cda374e01e39dcc59'/>
<id>c1330cb9a56d42632b1af54cda374e01e39dcc59</id>
<content type='text'>
The two outputs provided by the supported hardware share some settings,
so access to the other PWM is required when one of them is configured.

Instead of an explicit if to deterimine the other PWM just use
hwpwm ^ 1. Further atcbpwm is never NULL, so drop the corresponding
check.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Acked-by: Nicolas Ferre &lt;nicolas.ferre@microchip.com&gt;
Link: https://lore.kernel.org/r/20240709101806.52394-4-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The two outputs provided by the supported hardware share some settings,
so access to the other PWM is required when one of them is configured.

Instead of an explicit if to deterimine the other PWM just use
hwpwm ^ 1. Further atcbpwm is never NULL, so drop the corresponding
check.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Acked-by: Nicolas Ferre &lt;nicolas.ferre@microchip.com&gt;
Link: https://lore.kernel.org/r/20240709101806.52394-4-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: Allow pwm state transitions from an invalid state</title>
<updated>2024-07-10T15:53:52+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@baylibre.com</email>
</author>
<published>2024-06-28T10:35:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9dd42d019e6399e6e7d9e90759a61ff430625285'/>
<id>9dd42d019e6399e6e7d9e90759a61ff430625285</id>
<content type='text'>
While driving a PWM via the sysfs API it's hard to determine the right
order of writes to the pseudo files "period" and "duty_cycle":

If you want to go from duty_cycle/period = 50/100 to 150/300 you have to
write period first (because 150/100 is invalid). If however you start at
400/500 the duty_cycle must be configured first. The rule that works is:
If you increase period write period first, otherwise write duty_cycle
first. A complication however is that it's usually sensible to configure
the polarity before both period and duty_cycle. This can only be done if
the current state's duty_cycle and period configuration isn't bogus
though. It is still worse (but I think only theoretic) if you have a PWM
that only supports inverted polarity and you start with period = 0 and
polarity = normal. Then you can change neither period (because polarity
= normal is refused) nor polarity (because there is still period = 0).

To simplify the corner cases for userspace, let invalid target states
pass if the current state is invalid already.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Link: https://lore.kernel.org/r/20240628103519.105020-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
While driving a PWM via the sysfs API it's hard to determine the right
order of writes to the pseudo files "period" and "duty_cycle":

If you want to go from duty_cycle/period = 50/100 to 150/300 you have to
write period first (because 150/100 is invalid). If however you start at
400/500 the duty_cycle must be configured first. The rule that works is:
If you increase period write period first, otherwise write duty_cycle
first. A complication however is that it's usually sensible to configure
the polarity before both period and duty_cycle. This can only be done if
the current state's duty_cycle and period configuration isn't bogus
though. It is still worse (but I think only theoretic) if you have a PWM
that only supports inverted polarity and you start with period = 0 and
polarity = normal. Then you can change neither period (because polarity
= normal is refused) nor polarity (because there is still period = 0).

To simplify the corner cases for userspace, let invalid target states
pass if the current state is invalid already.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Link: https://lore.kernel.org/r/20240628103519.105020-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>pwm: xilinx: Simplify using devm_ functions</title>
<updated>2024-07-10T15:53:52+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@baylibre.com</email>
</author>
<published>2024-06-28T06:35:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=14b9dc66e93abbd16b22ac9153f658de1acaaf49'/>
<id>14b9dc66e93abbd16b22ac9153f658de1acaaf49</id>
<content type='text'>
There are devm variants for clk_prepare_enable() and pwmchip_add(); and
clk_prepare_enable() can be done together with devm_clk_get(). This
allows to simplify the error paths in .probe() and drop .remove()
completely.

With the remove callback gone, the last user of platform_get_drvdata()
is gone and so the call to platform_set_drvdata() can be dropped, too.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Reviewed-by: Sean Anderson &lt;sean.anderson@seco.com&gt;
Link: https://lore.kernel.org/r/20240628063524.92907-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There are devm variants for clk_prepare_enable() and pwmchip_add(); and
clk_prepare_enable() can be done together with devm_clk_get(). This
allows to simplify the error paths in .probe() and drop .remove()
completely.

With the remove callback gone, the last user of platform_get_drvdata()
is gone and so the call to platform_set_drvdata() can be dropped, too.

Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@baylibre.com&gt;
Reviewed-by: Sean Anderson &lt;sean.anderson@seco.com&gt;
Link: https://lore.kernel.org/r/20240628063524.92907-2-u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König &lt;ukleinek@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
